Jackie Kennedy: New Details of Her Heartbreak

When Jackie Kennedy returned to the White House in her bloodstained Chanel suit at 4 a.m. on Nov. 23, she took the elevator up to her private quarters on the third floor.

There, she sat in her bedroom and quietly confided her deepest fears to her personal assistant, Providencia Paredes, who was always by her side.

"She was scared," Paredes, 89, tells PEOPLE in a rare interview. "She cried and she said, 'I thought they might kill me too.'"

To the world, she was the black-veiled widow who planned her husband's funeral and mirrored the nation's grief, a model of dignity and grace. But to her young children, Caroline and John, she was "Mummy," who threw John Jr. a birthday party hours after his father's funeral, just as she had promised him a few days earlier.

"She did not want the children to think about what happened," confides Parades. "They were so young. She did not want them to be sad."

In the weeks and months that followed, Jackie moved to Georgetown and eventually, Manhattan, where she found the anonymity she craved.

Clint Hill, 81, the Secret Service agent guarding her during the Dallas motorcade, recalls the grief of the first year.

"She was sad," says Hill, who spent the following year watching over her in New York. "She didn't have the same radiance as before. But she grew stronger. She was already thinking about his legacy. She was always thinking ahead."

Read more about Jackie's life after the assassination and an exclusive excerpt of Clint Hill's new book Five Days In November in this week's PEOPLE magazine, on newsstands Friday.